Circuit for protecting traveling-wave tubes against faults of a power supply

Abstract

A traveling-wave tube protection circuit prevents faults in its associated power source from damaging it. The power source supplied DC voltages to the collector, slow-wave circuit, anode and cathode of the traveling-wave tube. A power source control circuit is provided between the anode electrode and the anode power source circuit and is used for applying a control voltage to the anode electrode. The control voltage stops the operation of the traveling-wave tube during the transient times which occur responsive to the initiation and the termination of the power source circuit operations. On shutdown, the power source control circuit also stops the supply of the control voltage to the anode electrode after the transient response is terminated. The power source control circuit has a high-frequency oscillator driven in response to either the initiation or the termination of the operation of the power supply means. To stop the operation of the traveling-wave tube, a control voltage is obtained from the output of the high-frequency oscillator, rectified and used to charge a capacitor which operates the oscillator for a predetermined time interval after the power supply ends.

What is claimed is: 
     
       1. A traveling-wave tube apparatus comprising: AC power supply means;   traveling-wave tube means having a collector electrode, a slow-wave circuit electrode, an anode electrode and a cathode electrode;   power source means responsive to said AC power supply for providing DC voltages to each of said electrodes;   high-frequency oscillator means driven in response to the initiation, termination and interruption in the operation of said AC power for providing a high frequency output;   first rectifying and smoothing circuit means for rectifying and smoothing said high frequency output to provide said anode electrode with a control voltage, said control voltage preventing the electron beam from flowing from said cathode electrode to said slow-wave circuit electrode; and   energizing means coupled between said AC power supply means and said high-frequency oscillator means for energing said high-frequency oscillator means,   whereby said traveling-wave tube is protected from damage during said initiation, termination and interruption.   
     
     
       2. The traveling-wave tube apparatus claimed in claim 1, wherein said energizing means includes second rectifying and smoothing means for rectifying and smoothing the output of said AC power supply means to provide a driving DC voltage, said driving DC voltage energizing said high-frequency oscillator means; and capacitor means coupled between said second rectifying and smoothing means and said high-frequency oscillator means for holding said driving DC voltage during a predetermined time interval after the start of said initiation and termination of the operation. 
     
     
       3. The traveling-wave tube apparatus claimed in claim 1 further comprising diode means connected between said anode and cathode electrodes and poled to be forwardly biased when said control voltage is supplied to said anode electrode.